My right hand has been developing this pain around the heel and base of the thumb area. Here are some characteristics of how my hand feels different
1. if i try to touch my index finger's nuckle with the tip of my thumb, i feel a much tighter stretch in the meaty thumb base than i do with my other hand.
2. putting pressure on that meaty thumb base doesn't necessarily hurt but the muscle feels constantly sore.
3. the major pain i feel is in the muscle on the outside blade of the hand below the pinky. it mainly hurts when i shake somebody's hand.

when i workout, nothing normally hurts in my hand, but the muscles do feel kinda funny. they almost feel like they are stretching and relaxing too much in the middle of different motions like pushups or what not. i was doing muscle ups this week and had my first real experience where a pain shot through my hand and wrist and i had to stop doing muscle ups. the pain didnt' continue, but i tried grabbing the rings again and could just tell that it wasn't going to happen. i did pullups and dips instead, and they didn't hurt at all. thus it has something to do with pressuring the outside blade of my hand.

i first noticed something was awry when shaking peoples hands began hurting. somebody could be giving a weak handshake and it would still hurt. i have had to struggle to keep a straight face each time this occurred. a few guys have given solid handshakes, and my hand starts screaming as a result.

i'm doing a lot more handstand work nowadays. my guess is that because my left shoulder is a lot less mobile than my right, i'm using my right hand to support more weight.

Yes, and it was always tied to overuse. I get the same things when going on long video game stunts and using the mouse and keyboard aggressively or playing way too much Guitar Hero. In fact my whole left hand went numb for 3 days after a 10 hour stint of it, I know, ridiculously silly on my part.

It's probably carpal tunnel syndrome as that's quite common amongst weight lifters. I've been suffering with it on and off for years and the only treatment I've had that improved things was a course of massage therapy aimed at releasing the transverse carpal ligament; basically it's just rubbing quite hard across the ligaments in the base of your wrist in order to free them. Other than that try different hand positions in the exercises that are causing you the most problems and try to keep your wrists as straight as possible when you're doing any pressing movements.

George,
Where in the heck does a new daddy and working man get the time to do a 10-hour stint of Guitar Hero?

Man, I can hardly scrape time together to watch a movie these days...

Grissim, my main suggestion is to cut way back or eliminate the handstand training for a while. Next, when you are doing handstands, you very much need to "squeeze" the heck out of the ground with the tips of all of your fingers while trying to keep the base of your index finger in contact with the ground. Loose fingers and wrists are a quick way to injury in handstands.

Take care of wrist/hand problems early, or end up with potentially chronic issues that affect all of your life activities later (since we humans use our hands for just a *few* things).

Also note that carpal tunnel syndrome-ish symptoms can also originate from the 1st rib / clavicular area or directly from the cervical spine. If you have had any tweaks to either of those areas recently, you might want to find a professional to sort that out.

Grissim, my main suggestion is to cut way back or eliminate the handstand training for a while. Next, when you are doing handstands, you very much need to "squeeze" the heck out of the ground with the tips of all of your fingers while trying to keep the base of your index finger in contact with the ground. Loose fingers and wrists are a quick way to injury in handstands.

Take care of wrist/hand problems early, or end up with potentially chronic issues that affect all of your life activities later (since we humans use our hands for just a *few* things).

Also note that carpal tunnel syndrome-ish symptoms can also originate from the 1st rib / clavicular area or directly from the cervical spine. If you have had any tweaks to either of those areas recently, you might want to find a professional to sort that out.

Dr. G ain't kidding, I know this first hand... (oops no pun intended)
In addition to what everyone said, shoulder/scapular mobility is super important if you plan to get on your hands again. I'd definitely invest time in increasing your ROM there. Unfortunately it's not as simple as doing lots of shoulder stretches. An adult will need to something that gives you better movement awareness of the area. Or at least that's been my experience. Feldenkrais is what worked for me but there are a lot of methods out there that are good.

damn it, i just started the new coach sommer book and now this happens.

interesting you mention the shoulder/clavicle area. about a year ago i got smashed into a matt pretty hard. it was a combination face plant and shoulder hit - reflexes made me pull my head back so my shoulder would take more of the force. my hands were tied up at the moment and pulled downward, stretching out my anterior delt. anyways i had to go to the emergency room. they said the muscle may have been a bit torn, but it wasn't anything super serious.

i had been doing yoga with some regularity before this. after i got messed up, i did yoga every morning for at least an hour. after about 2 months, my shoulder felt fine again, except that it couldn't support heavy weights overhead for a while. the shoulder is physically different now. like you can see this protrusion of muscle/flesh coming out that just isn't on the other side. 4 months after the debacle, my shoulder felt compelety fine. i literally have had no problems with it.

i have noticed though that it is more flexible than my other shoulder. i don't know if that's because of the injury or if my other shoulder is just behind. i've been focusing a lot of effort to make them equal. the reason why i think that i may have overused my hurt hand is because of its heightened flexibility - overhead positions are no problem with it nowadays.

because i wanna continue with coach sommer's book how should i change things up? i figure that movements in which the hand is outstretched on the floor puts more pressure on the wrist. thus are the rings safer since i can close my hand? i did planche pushups on the rings today and didn't have any problems. pulling motions feel fine altogether. should i substitute planche work on the ground with more back lever work?

my parallettes have a pretty big diamater for my hand. i feel that they have to stretch a bit to secure a grip. because they are a bar, i do feel that i am able to grab tighter and be more secure than on the ground, but for those split seconds where my hand relaxes too much on the paralletes, the uncomfortableness is much more pronounced than it would be on the ground.

i did l-sits on the parallettes today and that felt ok though. my hand probably gets aggravated when the wrist stretches only. that and the muscle ups